Heat indicator



NBv. 6, 1928.

J. E. ESHBAUGH HEAT INDICATOR Filed Jan. 31, 1927 3mm ,QW x M;

Patented Na. s, 1928.

UNITED "STATES .mssn EVERETT nsmmuon, or rum, MICHIGAN, xssienon To Ac SPARK COMP-ANY, orrrmr, MICHIGAN, COMPANY or MICHIGAN.

. 1,690,337 PATENT OFFICE- Prue i-iEA'r INDICATOR.

Application filed January 31, 1927, Serial No'. 164,848. g 1

This invention relates to heat indicators for use on internal combustion engines, particularly engines used on motor vehlcles.

In my invention] Ilniake use ofcertain paint substances which have the well known property of changing their color when heat above a, certain temperature is applied there to. I make use of a surface to which a coating of such paint is applied, this surface being the exposed end of a metal rod, the

other end of which preferably extends into the air space above'the Water in the upper tank of the radiator although it may dip down into the water. Preferably the rod is arranged-to extend through the radiator cap and at its line of connection withthe cap is equipped with a bushing of heat insulating material toprevent the esca e of heat.

My heat indicatoris pre erably provided with a top plate having a concave surface to the rear of the ainted surface of the rod which extends t rough the lower portion and up into the upper portion of the plate across the concave surface leaving the intermediate portion of the rod free and exposed toview. The cancavity serves as a reflecting surface rendering greatervisibility to the color change of the painted surface' The heat produced by the rising temperature of the water is conducted by the lower endof the metal rod tothe exposed painted partand when the temperature rises sufficiently high it will cause a change in the color of the paint, thus indicating to the reached.

i The invention is illustrated in the accompanying drawing inwhich: T

Figure'l is a sectional view looking from the rear showingthe'device applied to the driver that the danger. point has been radiator cap of anautomotive vehicle.

Figure ,2 Figure 1. i

Referring toYFigure 1, 1 indicates the radiator she-Hand 2 the upper radiator tank,

having an outturned annular flange 3 to which is secured the externally threaded fcollar 4 and onto which is screwedfa radiator cap 5. This cap has a threaded opening "6 for the, reception of the threaded extension 7 of the "top mounting plate8. The extension '7 is retained on thefcap by means'of a washer 9 and nut IOthreaded'on'to the end 7 which projects through the radiator cap.

asection-on theline 2-2 of aiconcave reflecting surface 11 and an openopening 12. It will be noted that the opening 12 is slightly larger than the end '16 to prevent any contact between the rod and the plate or the end 16 may be hexagonal so that any contact will be on a line. The lower end of the rod 15 terminates in the air space of the tank 2, but it may obviously extend down into the Water, or may be re- 7 placed by a tube.-

The concaved surface 11 is recessed as at 17 so that it may be free of the surface 18 painted on the upper ortion of the rod 15 V as suggested hereinbe ore.

The operation of my device is as follows Heat from the vapor of the water inthe tank 2 or from the water itself is transmitted from the lower portion of the rod'15 to the upper painted portion 18 and when a suificiently high degree of the temperature has been reached, the painted surface will change from its normal color which may be considered as yellow, to a different color, for

example, a bright red. The reflecting sur- 7 face in back of the paintedend 18 Will refleet and intensify the color change, thereby insuring greater visibility and rendering more pronounced the change in the heat con dition within the radiator. As the vapor cools, the colorchange will reverse.

I claim: 7

1. A heat indicator for internal combustion engines of motor vehicles, a radiator cap, a metal rod extending through an open 7.

ing in said cap, an upper plate portion hav ingia concave surface associated with said rodcto act as a reflector, an extension on said plate secured in said cap, a heat insulate a J j a groove in said'plate, said coated surface 2. In a heatlindicator, a member adapted to transmit heat from a body the temperature of which is to be indicated, means ining bushing in a bore in said extension and surroundmg saidrod, a coating'of heat sen sltlvepaint atthe upper end of said rod, andter-related with said member to indicate heat changes, and a framedreflector inter- Q 1 related with said member, said member extending entirely across the. reflecting surno 7 i face and passing through one edge of the reflector frame and extending into the second edge.

3. The invention of claim 2, said member being free of contact with said second edge.

The invention of claim 2, said reflecting surface having a curved outline.

5. In a heat indicator, a member adapted to transmit heat from av body the temperature of which is to be indicated, means associated with said member to indicate heat changes, a mounting for said indicator and an insulating bushing between said member and mounting.

6. In a heat indicator, :1 rod to transmit heat from a body the temperature of which is to be indicated, a. support for said rod, a rectangular frame attached to said support. a curved reflector in the rectangle of said frame at one side of said rod. and means; on said rod to indicate temperature changes.

7. The structure of claim (3, said means comprising a coating of heat sensitive paintand said reflector having a central groove in the rear of said coating of paint.

In testimony whereof Iaiiix my signature.

JESSE EVERETT ESHBAUGH. 

